1. Field of the Invention
The present invention relates to a cleaning blade for cleaning a non-transferred toner on an image carrier such as a photosensitive element, a photosensitive belt, an intermediate transfer belt, or the like, which is formed in an image forming apparatus that uses an electro-photographic method, such as a copying machine, a printer, a facsimile, a multi-function peripheral (MFP) thereof, or the like. The present invention also relates to a cleaning device including the cleaning blade, a process cartridge, and an image forming apparatus each including the cleaning device, and a holder member of the cleaning blade.
2. Description of the Related Art
In the related art, in a cleaning device of an image forming apparatus such as a copying machine or a printer, a technique that uses a cleaning blade for cleaning a non-transferred toner remaining on an image carrier such as a photosensitive element or an intermediate transfer belt is known (for example, refer to Japanese Patent Application Laid-open No. 10-198243 and Japanese Patent Application Laid-open No. 2001-249591).
Specifically, non-transferred toner, remaining on an image carrier after a transfer process, is removed by a cleaning blade that is in contact with the image carrier. The cleaning blade is one in which a blade member formed of a rubber material, or the like, is held by a blade holder (holder member) formed of a metal material, or the like, by being cantilevered, and an edge of the blade member is in contact with the image carrier over an longitudinal direction thereof.
Japanese Patent Application Laid-open No. 10-198243 discloses a technique which aims to decrease the contact pressure of a blade member to a photosensitive element at both ends in the longitudinal direction thereof. According to the technique, an attachment surface of a blade holder to which the blade member is attached is formed so that both ends in the longitudinal direction thereof are set apart from the photosensitive element.
The cleaning blade of the related art is in contact with the image carrier so that frictional resistance acting on the blade member increases at the end portions thereof in the longitudinal direction as compared to the middle portion thereof in the longitudinal direction. Thus, the blade member may be rolled up or cause vibration that makes noises.
Specifically, because both ends of the blade member in the longitudinal direction take positions, on the image carrier, in a non-image forming region or at positions near the non-image forming region, the amount of non-transferred toner supplied to the blade member is also smaller at both ends in the longitudinal direction than at the middle portion in the longitudinal direction. When the amount of the toner (the non-transferred toner supplied to the blade member) disposed between the blade member and the image carrier is insufficient, the image carrier becomes nearly in direct contact with the blade member. Thus, the frictional resistance acting on the blade member increases, and the blade member may be rolled up or cause vibration to make noises. As above, in the cleaning blade of the related art, it is likely that the blade member is rolled up or causes vibration to make noises at the ends thereof in the longitudinal direction.
On the other hand, according to the technique disclosed in Japanese Patent Application Laid-open No. 10-198243 described above, the blade member that follows the shape of the blade holder is attached to the blade holder so as to be apart from the photosensitive element at both ends in the longitudinal direction thereof. Thus, steps are formed at both of the end portions of the edge which is in contact with the photosensitive element, whereby insufficient cleaning is likely to occur at the positions of the end portions.